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Continuing from my previous question Is reversal of magnetic polarity in a planet an instantaneous occurence?

A change in magnetic flux is expected to generate an EMF.

In the case where the magnetic poles of a planet flip - What would be the magnitude of the induced voltage/current?

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An interesting question, but I'll have to go away and think about. You'd have to be a bit more specific and ask what current would be induced in some representative conductor, e.g. a railway line, as I'd guess the majority of the current flow would be in the core where we have little idea what's going on. Note also that the answer is probably "zero" because the flip may be fast on geological scales but probably still takes many years. The actual rate of flux change per second is probably negligably slow. – John Rennie Jun 19 '12 at 17:30
Just what I was getting at - If it were possible for such current to be generated, where would it flow? Through various conductive minerals available as seams/veins within Earth? Could one determine how close/distant reversal is by measuring current induced therein? – Everyone Jun 19 '12 at 18:35

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